IB Physics HL P1/P2

[Guest iblearner]

4 hours ago, David Lee said:

These questions look pretty similar to what I saw on Friday lololol

 

All rights go towards K.A Tsokos and Cambridge Press

*Sorry for bad resolution. My phone is pretty ****

this is just depressing. 

[Aleksandra Alex Zasadni]

To all of the people who found the exam "decent" and "alright"

I am really happy that you have mastered the exam and probably will get a very high grade on it. Unfortunately this will not be the case for many other students that have an understanding of physics but not to the point where they can completely disregard everything they have learned and just do questions that are this difficult.

Our teacher was working closely with the syllabus, using the exact same time, IBO advised and explored the new ideas presented in the syllabus, however I still found the exam very challenging because of the fact that the questions were not formulated in the way we were used to and because of the overall content of the questions. Due to the lacking resources as well as misleading revision guides, I was not able to complete all of the questions and for some I just tried to do "something".

As some of you have mentioned, it is not IBO's responsibility to make sure that the books have the informations we are being tested on. Yes, you are right, however in the beginning of the new syllabus, IBO has stated that they were working closely with the authors of the books to make  sure that the contents of the new syllabus is clearly described which definitely was not the case in our Pearson book, nor Oxford Revision Study Guide.

So once again, I am glad that you did well, but the exam structure should be made in a way, so that all level-students can be easily distinguished between, so if you are level 3 student, you should be able to have questions to prove your knowledge and thus have 3 as your grade from the exam. This year's exam was nothing like that. I was aiming for the excellent students, and the rest was forgotten and "doomed" to fail.

Edited May 8, 2016 by Aleksandra Alex Zasadni

[ibstudent081099]

What did you guys answer on the multiple choice of the percentage uncertainty? 

And the one on polarization?

[bynary]

42 minutes ago, ibstudent081099 said:

What did you guys answer on the multiple choice of the percentage uncertainty? 

And the one on polarization?

i put the percentage uncertainty to be 2

for the polarization, i put the curve that looked like a bell curve

[kevG]

48 minutes ago, ibstudent081099 said:

What did you guys answer on the multiple choice of the percentage uncertainty? 

And the one on polarization?

I put 2 as well, but apparently the answer was 1...

[YANA]

On 2016. 5. 7. at 2:28 PM, Daryl Ryan said:

I'm gonna be starting the IB this September and I'm gonna be taking Physics HL. Just wondering how the new Physics syllabus is like.

I don't remember about uncertainty, but I chose polarization one as flat line with intensity 0.

[Guest iblearner]

2 hours ago, ibstudent081099 said:

What did you guys answer on the multiple choice of the percentage uncertainty? 

And the one on polarization?

 

2 hours ago, bynary said:

i put the percentage uncertainty to be 2

for the polarization, i put the curve that looked like a bell curve

the answer for the first mcq question (percentage unc.) is 1. 

[Guest iblearner]

3 hours ago, Aleksandra Alex Zasadni said:

To all of the people who found the exam "decent" and "alright"

I am really happy that you have mastered the exam and probably will get a very high grade on it. Unfortunately this will not be the case for many other students that have an understanding of physics but not to the point where they can completely disregard everything they have learned and just do questions that are this difficult.

Our teacher was working closely with the syllabus, using the exact same time, IBO advised and explored the new ideas presented in the syllabus, however I still found the exam very challenging because of the fact that the questions were not formulated in the way we were used to and because of the overall content of the questions. Due to the lacking resources as well as misleading revision guides, I was not able to complete all of the questions and for some I just tried to do "something".

As some of you have mentioned, it is not IBO's responsibility to make sure that the books have the informations we are being tested on. Yes, you are right, however in the beginning of the new syllabus, IBO has stated that they were working closely with the authors of the books to make  sure that the contents of the new syllabus is clearly described which definitely was not the case in our Pearson book, nor Oxford Revision Study Guide.

So once again, I am glad that you did well, but the exam structure should be made in a way, so that all level-students can be easily distinguished between, so if you are level 3 student, you should be able to have questions to prove your knowledge and thus have 3 as your grade from the exam. This year's exam was nothing like that. I was aiming for the excellent students, and the rest was forgotten and "doomed" to fail.

preach

[bynary]

Just now, iblearner said:

 

the answer for the first mcq question (percentage unc.) is 1. 

wouldn't it be 2 because we are given the diameter of the sphere so the % unc. is doubled when you find the radius?

[Stewart.M]

23 hours ago, Sandy said:

Did you get time to go through the whole paper?

Yeah I did, Whether or not the answers were correct is another story.

 

[Guest iblearner]

Just now, bynary said:

wouldn't it be 2 because we are given the diameter of the sphere so the % unc. is doubled when you find the radius?

Some things get cancelled and you get 1 as the ratio, i dont quite remember the exact question but majority in my grade got the same answer. :))

[bynary]

4 minutes ago, iblearner said:

Some things get cancelled and you get 1 as the ratio, i dont quite remember the exact question but majority in my grade got the same answer. :))

agree to disagree  

[David Lee]

I got 1 for that uncertainty

 

For the polarizarion

I thought it was malus's law

So though the graph should look cos^2 x

And think it stated the domain so i just drew the graph out and figured it out from there 

:/ 

 

[Polybos]

When you divide the diameter by two the absolute uncertainty is also divided by two. So percentage uncertainty stays the same. Therefore when you cube it the percentage uncertainty is the same anyway. Just think of it as doing d/2 in the formula for the sphere. 2 is just a constant so it doesn't matter for percentage uncertainty as it does not have an uncertainty itself. This is quite important for paper 3 so I would advise you to learn it. 

For the polarizer question the light was already horizontally polarized, so when it went through the vertical polarizer nothing would go through regardless of what the first polarizer was. A bit of a trick question, but oh well. 

[bynary]

3 minutes ago, Polybos said:

For the polarizer question the light was already horizontally polarized, so when it went through the vertical polarizer nothing would go through regardless of what the first polarizer was. A bit of a trick question, but oh well. 

consider the situation when theta=45°

by malus' law the intesity after the first polarizer is I=I_0 cos^2(45) = I_0/2

then the angle from the first polarizer to the second is 45° => I_1 = I cos^2(45) = 0.25*I_0 =/= 0

Therefore there is some light coming out of it. (I tried doing it after the paper with 3 polarizers (one was to polarize the light))

[Polybos]

1 minute ago, bynary said:

consider the situation when theta=45°

by malus' law the intesity after the first polarizer is I=I_0 cos^2(45) = I_0/2

then the angle from the first polarizer to the second is 45° => I_1 = I cos^2(45) = 0.25*I_0 =/= 0

Therefore there is some light coming out of it. (I tried doing it after the paper with 3 polarizers (one was to polarize the light))

Well, the thing is that the light was horizontally polarized initially. When it then goes through a vertical polarizer everything gets stopped. The first polarizer was just there to trick you. 

[Stewart.M]

For the Malus's Law you just had to do Cos0 which is 1 and then the amplitude was 16 so there you go 

 

[bynary]

1 minute ago, Polybos said:

Well, the thing is that the light was horizontally polarized initially. When it then goes through a vertical polarizer everything gets stopped. The first polarizer was just there to trick you. 

Can you show me where my error in my calculations is?

[Polybos]

Just now, bynary said:

Can you show me where my error in my calculations is?

Your calculation is good. The problem is that it was a trick question. You assume it was unpolarized light that hit the polarizer which is what the IB usually does. However this time the light was horizontally polarized initially. If you want you can think of it as having three polarizers. One horizontal, one that rotates and one vertical. Then you can use your formula and see that cos 90 = 0.

[indimpi]

http://physics.stackexchange.com/questions/61918/three-polarizers-45-apart

 

This illustrates the problem from the exam, light does in fact come through.